What is the Difference Between Oncogenes and Oncoprotein

The key difference between oncogenes and oncoprotein is that oncogenes are cancerous genes formed due to a change or mutation in the DNA sequence of the proto-oncogene while oncoprotein is the protein coded by an oncogene which is responsible for an uncontrollable cell division.

Cells divide and produce new cells via cell cycles. The cell cycle is a highly regulated process, and different types of regulatory proteins are involved in this process. These regulatory proteins are coded by genes called proto-oncogenes. Proto-oncogenes are normal genes that code for positive cell cycle regulators. Trillions of living cells originate, divide, and die in a regulated manner in living organisms. Regulatory proteins synthesized by proto-oncogenes coordinate all these events perfectly in living cells. Hence, proto-oncogenes are extremely important genes in living cells. However, proto-oncogenes can be converted into oncogenes due to mutations. Oncogenes are cancerous genes. These genes synthesize different proteins known as oncoproteins. Oncoproteins are responsible for tumorigenic cell growth.

CONTENTS

1. Overview and Key Difference
2. What are Oncogenes 
3. What is an Oncoprotein
4. Similarities – Oncogenes and Oncoprotein
5. Oncogenes vs Oncoprotein in Tabular Form
6. Summary – Oncogenes vs Oncoprotein

What are Oncogenes?

Oncogenes are the genes responsible for cancer development. Cancer is a result of uncontrolled cell division. When the DNA sequence of the proto-oncogene is changed or mutated, oncogenes are formed. Proto-oncogenes become oncogenes due to several genetic modifications or mechanisms such as mutations, gene amplification, and chromosomal translocations.

When oncogenes are expressed, they produce oncoproteins, which influence and interrupt the normal cell cycle. Oncogenes produce inhibitors of the cell cycle which keep the cells dividing continuously even during the unfavourable conditions for cell division. They also produce positive regulators that keep cells active till the formation of cancer. Oncogenes work towards cancer formation by promoting uncontrolled cell division, lowering cell differentiation, and inhibiting programmed cell death (apoptosis). Some people are more prone to have proto-oncogenes converting to oncogenes and develop cancers due to cancer-causing agents such as radiation, viruses, and environmental toxins.

What is an Oncoprotein?

Oncoprotein is a product of an oncogene. In other words, oncogenes synthesize oncoproteins. Oncoproteins are different types of proteins that are responsible for tumorigenic cell growth. They drive cancer development and congenital disorders. Oncoporteins promote the transformation of cells into tumors. It is done by dysregulating the signalling pathways involved in cell growth, division, and death.

Examples of three viral oncoproteins are SV40 large T antigen, adenovirus E1A, and human papillomavirus E7. These three oncoproteins are able to activate quiescent cells to re-enter the cell cycle. Since the presence of oncoproteins indicates cancer development, some of the oncoproteins are utilized as tumor markers. Many anticancer drugs target oncoproteins.

What are the Similarities Between Oncogenes and Oncoprotein?

• Oncogenes code for oncoproteins.
• Both oncogenes are oncoproteins are responsible for tumorigenic cell growth.
• These oncogenes and oncoproteins regulate the cell cycle negatively.

What is the Difference Between Oncogenes and Oncoprotein?

Oncogene is a tumour-inducing gene formed due to a mutation that occurred in proto-oncogene. Oncoprotein is the product coded by an oncogene. So, this is the key difference between oncogenes and oncoprotein. Moreover, oncogenes are composed of nucleic acids, while oncoproteins are proteins made up of amino acids.

The following infographic lists the differences between oncogenes and oncoprotein in tabular form for side by side comparison.

Summary – Oncogenes vs Oncoprotein

Proto-oncogenes are the normal genes that regulate cell division. Protooncogenes code positive cell cycle regulator proteins that are essential for normal cell division. Proto-oncogenes become oncogenes as a result of a mutation or overexpression. Oncogene is a tumour-inducing gene or a cancerous gene. Oncoprotein is the resultant protein of an oncogene. Oncoproteins promote the transformation of normal cells into cancer cells. Thus, this is the summary of the difference between oncogenes and oncoprotein.

Reference:

1. “Oncogene.” Wikipedia, Wikimedia Foundation, 10 Aug. 2021.
2. Cooper, Geoffrey M. “Oncogenes.” The Cell: A Molecular Approach. 2nd Edition., U.S. National Library of Medicine, 1 Jan. 1970.

Image Courtesy:

1. “Oncogenes illustration” – Released by the National Cancer Institute, an agency part of the National Institutes of Health, with the ID 2351 (Public Domain) via Commons Wikimedia
2. “4giz.E6” By Opabinia regalis – Own work (CC BY-SA 4.0) via Commons Wikimedia